Semiconductor light-emitting device

ABSTRACT

A semiconductor light-emitting device includes a substrate, an LED chip mounted on the substrate, and a resin package covering the LED chip. The substrate includes a base and a wiring pattern formed on the base. The resin package includes a lens. The base includes an upper surface, a lower surface and a side surface extending between the upper surface and the lower surface. The LED chip is mounted on the upper surface of the base. The side surface of the base is oriented in a lateral direction. The wiring pattern includes a pair of first mount portions and a pair of second mount portions. The paired first mount portions are formed on the lower surface of the base. The paired second mount portions are oriented in the lateral direction and offset from the side surface of the base in the lateral direction.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a semiconductor light-emitting devicethat includes an LED chip as the light source.

2. Description of the Related Art

Conventionally, various semiconductor light-emitting devices that useLED (light-emitting diode) chips as the light sources are known. Anexample of semiconductor light-emitting device is disclosed inJP2009-21472. The semiconductor light-emitting device shown in FIGS. 1-5of this document includes a pair of leads, an LED chip and a resinpackage. Each of the leads has a portion exposed from the resin package,and the exposed portion includes a mount portion and a connectingportion. Each mount portion includes a portion extending perpendicularlyto the optical axis (mount portion 11A, 11B) and a portion extendingalong the optical axis (mount portion 12A, 12B). The mount portion andthe connecting portion are formed by bending the exposed portion of thelead a plurality of times.

According to the conventional technique of bending a lead a plurality oftimes, it is relatively difficult to make each mount portion at adesired position or into a desired angle. Thus, the conventionalsemiconductor light-emitting device tends to require a highmanufacturing cost. Moreover, in the conventional semiconductorlight-emitting device, the mount portion is spaced away from the resinpackage. Thus, there is still room for improvement regarding sizereduction of the semiconductor light-emitting device.

SUMMARY OF THE INVENTION

The present invention has been conceived under the above-describedcircumstances. It is therefore an object of the present invention torealize size reduction of a semiconductor light-emitting device that canbe used as either a top view type light source or a side view type lightsource.

According to an embodiment of the present invention, there is provided asemiconductor light-emitting device comprising a substrate including abase and a wiring pattern formed on the base, an LED chip mounted on thesubstrate, and a resin package covering the LED chip and including alens positioned in front of the LED chip. The base includes a firstprimary surface, a second primary surface and a first side surface. Thefirst primary surface faces a first side in a first direction, and theLED chip is mounted on the first primary surface. The second primarysurface faces a second side opposite to the first side in the firstdirection and is parallel to the first primary surface. The first sidesurface is connected to both of the first primary surface and the secondprimary surface and faces a first side in a second directionperpendicular to the first direction. The wiring pattern includes a pairof first mount portions and a pair of second mount portions. The pairedfirst mount portions are formed on the second primary surface and spacedapart from each other in a third direction perpendicular to both of thefirst direction and the second direction. The paired second mountportions face the first side in the second direction, are positioned onthe first side of the first side surface in the second direction and arespaced apart from each other in the third direction.

Preferably, the resin package includes a foundation portion positionedcloser to the substrate than the lens is.

Preferably, the foundation portion includes an end surface spaced awayfrom the substrate toward the first side in the first direction. Thelength from the second primary surface to the end surface of thefoundation portion is not less than one half the length from the secondprimary surface to the center of the lens.

Preferably, the foundation portion includes a first foundation portionside surface that is flush with the first side surface of the base.

Preferably, the thickness of the foundation portion in the firstdirection is larger than the thickness of the base in the firstdirection.

Preferably, the center of gravity of an entirety including thesubstrate, the LED chip and the resin package is closer to the substratethan the middle point between the second primary surface and the top ofthe lens is.

Preferably, the base includes a second side surface facing a second sidein the second direction and parallel to the first side surface. Asviewed in the first direction, the center of the lens is offset in thesecond direction from the middle point between the first side surfaceand the second side surface.

Preferably, the base includes a second side surface facing a second sidein the second direction and parallel to the first side surface. Thefoundation portion includes a second foundation portion side surfaceparallel to the first foundation portion side surface.

Preferably, the second foundation portion side surface is flush with thesecond side surface of the base.

Preferably, the wiring pattern includes a pair of bonding portionsformed on the first primary surface. The LED chip is mounted on one ofthe bonding portions. Each of the bonding portions is electricallyconnected to a respective one of the first mount portions.

Preferably, the base includes a third side surface and a fourth sidesurface facing a first side and a second side, respectively, in thethird direction and parallel to each other. The wiring pattern includesa pair of detour portions connected to both of the first mount portionsand the bonding portions and formed on the third side surface and thefourth side surface, respectively.

Preferably, the paired detour portions cover ends of the third sidesurface and the fourth side surface which are closer to the first sidesurface on the first side in the second direction. The paired firstmount portions cover an end of the second primary surface on the firstside in the second direction.

Preferably, the paired detour portions cover the third side surface andthe fourth side surface at a region from an end on the first side in thesecond direction to an end on the second side in the second direction,and the paired first mount portions cover the second primary surface ata region from an end on the first side in the second direction to an endon the second side in the second direction.

Preferably, the wiring pattern includes a conductive layer formed on thebase, and a plating layer covering at least part of the conductivelayer.

Preferably, each of the detour portions and the first mount portionscomprises the conductive layer and the plating layer formed on theconductive layer.

Preferably, a first end surface of the conductive layer providing thedetour portion, which is an end surface on the first side in the seconddirection, and a second end surface of the conductive layer providingthe first mount portion, which is an end surface on the first side inthe second direction, are covered by the plating layer.

Preferably, the first end surface and the second end surface are flushwith the first side surface, and the second mount portion includes theplating layer covering the first end surface and the second end surface.

Preferably, an edge of the plating layer covering the first end surfaceand the second end surface covers the first side surface.

Preferably, the conductive layer contains Cu.

Preferably, the paired bonding portions comprise a first bonding portionincluding a first extension extending from the first side toward thesecond side in the third direction and a second bonding portionincluding a second extension extending from the second side toward thefirst side in the third direction. The LED chip is mounted on the firstextension.

Preferably, the length of the first extension in the second direction isnot less than one half the length of the base in the second direction.

Preferably, the first extension includes a first opening positioned onthe first side of the LED chip in the third direction and penetrating inthe first direction.

Preferably, the first extension includes a first projection overlappingthe LED chip as viewed in the third direction and projecting toward thesecond side in the third direction. The length from the LED chip to afront end of the first projection on the second side in the thirddirection is not less than the length of the LED chip in the seconddirection.

Preferably, the first extension includes a second projection projectingfrom each end in the second direction toward the second side in thethird direction.

Preferably, the front end of the second projection on the second side inthe third direction is on the second side of the front end of the firstprojection in the third direction.

Preferably, the semiconductor light-emitting device according to thepresent invention further comprises a wire connecting the LED chip andthe second extension.

Preferably, the second extension is spaced apart from the LED chip asviewed in the third direction.

Preferably, the semiconductor light-emitting device according to thepresent invention further comprises a resist film interposed between thefirst and the second bonding portions and the resin package. The resistfilm includes a second opening that exposes part of the first bondingportion. The first extension includes a portion exposed through thesecond opening, and the LED chip is mounted on this portion of the firstextension.

Preferably, the lens includes an optical axis extending in the firstdirection and an aspheric surface of which curvature reduces asproceeding from the center toward the periphery.

Preferably, the lens has a diameter not less than six times the lengthof a side of the LED chip as viewed in the first direction.

Other features and advantages of the present invention will become moreapparent from detailed description given below with reference to theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a semiconductor light-emitting deviceaccording to a first embodiment of the present invention;

FIG. 2 is a plan view showing the semiconductor light-emitting device ofFIG. 1;

FIG. 3 is a sectional view taken along lines III-III in FIG. 2;

FIG. 4 is a schematic enlarged view of FIG. 3;

FIG. 5 is a sectional view taken along lines V-V in FIG. 2;

FIG. 6 is a schematic enlarged view of FIG. 5;

FIG. 7 is a sectional view taken along lines VII-VII in FIG. 2;

FIG. 8 is a schematic enlarged view of FIG. 7;

FIG. 9 is a sectional view taken along lines IX-IX in FIG. 3;

FIG. 10 is a schematic enlarged view of FIG. 9;

FIG. 11 is a perspective view showing a step of process for making thesemiconductor light-emitting device of FIG. 1;

FIG. 12 is a perspective view showing a step subsequent to FIG. 11;

FIG. 13 is a perspective view showing a step subsequent to FIG. 12;

FIG. 14 is a perspective view showing a step subsequent to FIG. 13;

FIG. 15 is a side view showing an example of the state in which thesemiconductor light-emitting device of FIG. 1 is mounted on a circuitboard;

FIG. 16 is a side view showing an example of the state in which thesemiconductor light-emitting device of FIG. 1 is mounted on a circuitboard;

FIG. 17 is a plan view of a semiconductor light-emitting deviceaccording to a second embodiment of the present invention;

FIG. 18 is a sectional view taken along lines XVIII-XVIII in FIG. 17;

FIG. 19 is a plan view showing a step of a process for making thesemiconductor light-emitting device of FIG. 17;

FIG. 20 is a side view showing an example of the state in which thesemiconductor light-emitting device of FIG. 17 is mounted on a circuitboard;

FIG. 21 is a plan view of a semiconductor light-emitting deviceaccording to a third embodiment the present invention;

FIG. 22 is a plan view of a semiconductor light-emitting deviceaccording to a fourth embodiment the present invention;

FIG. 23 is a plan view of a semiconductor light-emitting deviceaccording to a fifth embodiment the present invention;

FIG. 24 is a plan view of a semiconductor light-emitting deviceaccording to a sixth embodiment the present invention;

FIG. 25 is a sectional view taken along lines XXV-XXV in FIG. 24; and

FIG. 26 is a graph showing the results of simulation analysis performedwith respect to the heat dissipation ability of semiconductorlight-emitting devices.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention are described below withreference to the accompanying drawings.

FIGS. 1-10 show a semiconductor light-emitting device according to afirst embodiment of the present invention. The illustrated semiconductorlight-emitting device 101 includes a substrate 200, an LED chip 300, awire 400 and a resin package 500.

As shown in FIGS. 1-3, the substrate 200 includes a base 210 and awiring pattern 220 formed on the base 210.

The base 210 is in the form of a rectangular parallelepiped and made ofe.g. glass epoxy resin. The base 210 has an upper surface 210 a and alower surface 210 b which are parallel to each other. The base 210further includes a side surface 210 c and a side surface 210 d which areparallel to each other, and a side surface 210 e and a side surface 210f which are parallel to each other. The upper surface 210 a is a flatsurface facing a first side in the direction x, and the lower surface210 b is a flat surface facing a second side in the direction x. Theside surface 210 c is a flat surface facing a first side in thedirection y, and the side surface 210 d is a flat surface facing asecond side in the direction y. The direction y is perpendicular to thedirection x. The side surface 210 e is a flat surface facing a firstside in the direction z, and the side surface 210 f is a flat surfacefacing a second side in the direction z. The direction z isperpendicular to both of the direction x and the direction y. Each sidesurface 210 c, 210 d is in the form of a rectangle elongated in thedirection z. Each side surface 210 e, 210 f is in the form of arectangle elongated in the direction y. The length of the base 210 inthe direction z is longer than the length of the base 210 in thedirection y. For instance, the base 210 is about 2.9 mm in length in thedirection z, about 2.5 mm in length in the direction y and about 0.7 mmin thickness.

The wiring pattern 220 is made of a metal such as Cu, Ni, Ag or Au. Asshown in FIGS. 1-3, the wiring pattern 220 includes bonding portions221, 222, detour portions 223, 224, and mount portions 225, 226, 227,228. The bonding portions 221 and 222 are provided on the upper surface210 a of the base 210. On the bonding portion 221 is bonded the LED chip300. The detour portions 223 and 224 are connected to the bondingportions 221 and 222, respectively and provided on the side surfaces 210e, 210 f of the base 210. The mount portions 225 and 226 are provided onthe lower surface 210 b of the base 210 and spaced apart from each otherin the direction z. The mount portions 225 and 226 are connected to thedetour portions 223 and 224, respectively. The mount portions 227 and228 face the first side in the direction y. The mount portions 225, 226and the mount portions 227, 228 are used for mounting the semiconductorlight-emitting device 101 on e.g. a circuit board. The mount portions225 and 226 are used for surface-mounting the light-emitting device insuch a manner that the lower surface 210 b faces the circuit board. Thedetailed structure of the wiring pattern 220 is described later.

The LED chip 300 shown in FIG. 3 includes a quaternary semiconductorlayer made up of an n-type semiconductor layer made of e.g. AlGaInP, anactive-layer and a p-type semiconductor layer arranged one on top ofanother, and emits e.g. orange light. Two electrodes are provided on theLED chip 300. One of the electrodes is provided on the lower surface andbonded to the bonding portion 221 via conductive paste. The other one ofthe electrodes is provided on the upper surface. An end of the wire 400is bonded on this electrode. Another end of the wire 400 is bonded onthe bonding portion 222. In this embodiment, only one wire 400 is bondedon the LED chip 300 (so-called single wire type). For instance, the LEDchip 300 is in the form of a square having a size of 260×260 μm asviewed in the direction x, and has a thickness of about 170 μm. The LEDchip 300 may be of the type that emits green light, including asemiconductor layer made of InGaN, or of the type that emits blue light.

As shown in FIGS. 1-3, the resin package 500 covers the LED chip 300 andthe upper surface 210 a of the base 210. The resin package 500 is madeof e.g. an epoxy resin or silicone resin that transmits light from theLED chip 300. The resin package 500 includes a foundation portion 510and a dome-shaped portion 520. The dome-shaped portion 520 bulges towardthe first side in the direction x and has a lens 520 a close to the topend of the dome-shaped portion 520. The lens 520 a is positioned to facethe LED chip 300 and has an optical axis La extending in the directionx. The lens 520 a is provided for increasing directivity of the lightfrom the LED chip 300. In this embodiment, the lens 520 a has anaspheric surface, and the curvature reduces as proceeding from thecenter toward the periphery.

The foundation portion 510 is closer to substrate 200 than the lens 520a is and sandwiches the dome-shaped portion 520 from opposite sides inthe direction y. The foundation portion 510 has side surfaces 510 a, 510b, 510 c and 510 d. The side surface 510 a is a flat surface facing thefirst side in the direction y and flush with the side surface 210 c ofthe base 210, as shown in FIG. 2. The side surface 510 b is a flatsurface facing the second side in the direction y and flush with theside surface 210 d of the base 210. The side surfaces 510 c and 510 dare connected to both of the side surfaces 510 a and 510 b and inclinedwith respect to x-y plane. In this embodiment, the side surfaces 510 cand 510 d are inclined to become further away from the LED chip 300 asviewed in the direction x as proceeding toward the base 210 (proceedingtoward the second side in the direction x). The width W1 of thefoundation portion 510 in the direction z at the contact interface areawith the substrate 200 (wiring pattern 220) is smaller than the width W2of the substrate 200 in the direction z. Thus, the wiring pattern 220(bonding portions 221, 222) on the upper surface 210 a of the base 210is exposed from the foundation portion 510 at the ends in the directionz.

For instance, the dimensions of the semiconductor light-emitting device101 in the direction x may be (see FIG. 3) about 3.3 mm in length L1from the lower surface 210 b of the base 210 to the center of the lens520 a, and about 1.7 mm in length L2 from the lower surface 210 b to theend of the foundation portion 510 on the first side in the direction x.The length L2 is set to be not less than one half the length L1. Asshown in FIG. 3, the thickness L3 of the foundation portion 510 in thedirection x is larger than the thickness t of the base 210 in thedirection x. The larger the thickness L3 of the foundation portion 510is, the more stable the posture of the light-emitting device is when thelight-emitting device is mounted as a side-view type. On the other hand,in view of the directivity of the lens 520 a, the thickness L3 of thefoundation portion 510 is set in such a manner that light having apredetermined angle α from the center of the upper surface of the LEDchip 300 does not impinge on the foundation portion 510. For instance,the angle α is 55°. However, the angle is not limited to this and may beset in the range of 45-60°. Further, in this embodiment, as shown inFIG. 3, when the center of gravity of the entirety including thesubstrate 200, the LED chip 300 and the resin package 500 is expressedas “G”, and the middle point between the lower surface 210 b of the base210 and the top of the lens 520 a is expressed as “C”, the gravity G iscloser to the substrate 200 than the middle point C is.

As will be understood from FIGS. 1, 2 and 9, in the wiring pattern 220of this embodiment, each of the detour portions 223 and 224 covers therange extending from the end on the first side (closer to the sidesurface 210 c) to the end on the second side in the direction y. As willbe understood from FIGS. 1, 5 and 7, each of the mount portions 225 and226 covers the range extending from the end on the first side to the endon the second side in the direction y. Each of the bonding portions 221and 222 includes a portion that covers the range extending from the endon the first side to the end on the second side in the direction y.

The wiring pattern 220 is made up of conductive layers and a platinglayer arranged on the conductive layers. In this embodiment, as shown inFIGS. 4, 6, and 10, the wiring pattern 220 is made up of conductivelayers 220A, 220B, 220C and a plating layer 220D arranged one on top ofanother. For instance, the conductive layer 220A is made of Cu, theconductive layer 220B is made of Ni, the conductive layer 220C is madeof Au, and the plating layer 220D is made of Sn. The plating layer 220Dcovers the conductive layers at portions that are not covered by theresin package 500.

Specifically, as will be understood from FIGS. 3, 4, 9 and 10, eachdetour portion 223, 224 is made up of the conductive layers 220A, 220B,220C and the plating layer 220D arranged one on top of another. As willbe understood from FIGS. 9 and 10, the end surfaces 223 a, 224 a of theconductive layers 220A, 220B, 220C, which constitute the detour portions223, 224, on the first side in the direction y are flush with the sidesurface 210 c of the base 210. The end surfaces 223 a, 224 a are coveredby plating layers 220D, and the plating layers 220D covering the endsurfaces 223 a, 224 a provide the mount portions 227, 228. As will beunderstood from FIGS. 5-8, each mount portion 225, 226 is made up ofconductive layers 220A, 220B, 220C and a plating layer 220D arranged oneon top of another. The end surfaces 225 a, 226 a of the conductivelayers 220A, 220B, 220C, which constitute the mount portions 225, 226,on the first side in the direction y are flush with the side surface 210c of the base 210. The end surfaces 225 a, 226 a are covered by theplating layers 220D, and the plating layers 220D covering the endsurfaces 225 a, 226 a provide the mount portions 227, 228. The edge ofthe plating layers 220D covering the end surface 225 a, 226 a, projectsby a small amount onto the side surface 210 c, to cover part of the edgeof the side surface 210 c. In this embodiment, the plating layers 220Dproviding the mount portions 227, 228 is formed so as to substantiallyavoid the side surface 210 c. Thus, the side surface 210 c is exposedfrom the mount portions 227, 228 generally entirely.

Examples of the thickness of each layer of the wiring pattern 220 are asfollows. The thickness of the conductive layer 220A may be about 20 μm,the thickness of the conductive layer 220B may be about 10 μm, thethickness of the conductive layer 220C may be about 0.2 μm, and thethickness of the plating layer 220D may be about 8 μm. In FIGS. 2, 5, 7and 9, the thickness of the plating layer 220D is shown as exaggerated.

The end on the first side (closer to the side surface 210 c) of thewiring pattern 220 in the direction y is exposed to have a C-shape madeup of three straight portions and projects to the first side in thedirection y from the side surface 210 c by the amount corresponding tothe thickness of the plating layer 220D. The portion of the wiringpattern 220 that faces the first side in the direction y and positionedon the first side of the side surface 210 c in the direction y providesthe mount portion 227, 228. The mount portions 227 and 228 are spacedapart from each other in the direction z. The mount portions 227 and 228are used for surface-mounting the light-emitting device in such a mannerthat the side surface 210 c faces a circuit board.

A process for making the semiconductor light-emitting device 101 isdescribed below with reference to FIGS. 11-14. First, as shown in FIG.11, a base aggregate board 210′ as a material for a base 210 isprepared. The base aggregate board 210′ has a cross section extendingalong x-z plane and is elongated in the direction y like a bar. Then, asshown in FIG. 12, conductor patterns 220′ are formed on the baseaggregate board 210′. The conductor patterns 220′ are formed bylaminating metal materials for the conductive layers 220A, 220B, 220Cone on top of another, and provided at opposite edges of the baseaggregate board 210′ in the direction z. Each conductor pattern 220′includes portions to become bonding portions 221, 222, detour portions223, 224, and mount portions 225, 226 as connected to each other in thedirection y. Then, as shown in FIG. 13, LED chips 300 are mounted atpredetermined portions of a conductor pattern 220′ (at portionscorresponding to the bonding portions 221). Then, a wire 400 is bondedto each of the LED chips 300. Then, as shown in FIG. 14, a resin mold500′ is formed on the base aggregate board 210′. The resin mold 500′includes portions to become resin packages 500 as connected to eachother in the direction y. In this way, a semiconductor light-emittingdevice aggregate member 101′ (hereinafter referred to as aggregatemember 101′) is obtained. Then, the aggregate member 101′ is cut alongx-y plane at predetermined intervals in the direction y, whereby dividedmembers (not shown) are obtained. Each divided member is different fromthe semiconductor light-emitting device 101 in that it does not includea plating layer 220D. One of the cut end surfaces of the divided memberincludes an end surface of the base 210 (e.g. side surface 210 c), anend surface of the resin package 500 (e.g. side surface 510 a of thefoundation portion 510), and end surfaces of the conductive layers 220A,220B, 220C, and these end surfaces are flush with each other. The otherone of the cut end surfaces of the divided member includes an endsurface of the base 210 (side surface 210 d, which is on the oppositeside of the side surface 210 c in the direction y), an end surface ofthe resin package 500 (side surface 510 b, which is on the opposite sideof the side surface 510 a in the direction y), and end surfaces of theconductive layers 220A, 220B, 220C, and these end surfaces are flushwith each other. Then, a plating layer 220D is formed on the metalexposed portions of the divided member, whereby the semiconductorlight-emitting device 101 is obtained.

As a result of this manufacturing process, the portions of the wiringpattern 220 which are on the opposite side of the mount portions 227,228 (second mount portion) in the direction y project from the sidesurface 210 d to the opposite side in the direction y by the amountcorresponding to the thickness of the plating layer 220D. As will beunderstood from this, the portions of the wiring pattern 220 which areon the opposite side of the mount portions 227, 228 in the direction yhave the same structure as that of the mount portions 227, 228. Thus,the portions of the wiring pattern 220 which are on the opposite side ofthe mount portions 227, 228 in the direction y can be utilized as asecond mount portion when the light-emitting device is mounted, with theside surface 210 d, which is on the opposite of the side surface 210 cin the direction y facing a circuit board.

The advantages of the semiconductor light-emitting device 101 aredescribed below.

According to this embodiment, the semiconductor light-emitting device101 can be surface-mounted on a circuit board. In the case where themount portions 225 and 226 are used for mounting, the lower surface 210b of the base 210 is oriented toward the circuit board S, as shown inFIG. 15. In this case, the semiconductor light-emitting device 101 isused as a top view type light source that emits light in a direction inwhich the circuit board S faces. On the other hand, in the case wherethe mount portions 227 and 228 are used for mounting, the side surface210 c of the base 210 is oriented toward the circuit board S, as shownin FIG. 16. In this case, the semiconductor light-emitting device 101 isused as a side view type light source which emits light in a directionin which the circuit board S extends. For instance, the semiconductorlight-emitting device 101 of this embodiment can be used as autofocusassist light of a digital camera.

The mount portions 225, 226 and the mount portions 227, 228 are providedby the wiring pattern 220 in the form of a thin film formed on the base210. Thus, when the light-emitting device is surface-mounted by usingsolder, either of the lower surface 210 b or the side surface 210 c canbe brought into close contact with the circuit board S via soldersubstantially in parallel to the circuit board. This assures that thelight-emitting device is mounted in a desired posture on a circuit boardS whether it is used as a top view type light source or a side view typelight source.

Since the mount portions 225, 226 and the mount portions 227, 228 areprovided by the wiring pattern 220, the semiconductor light-emittingdevice 101 is suitable for size reduction as compared with the structurein which the mount portions are made by bending a metal lead, forexample.

The lens 520 a is an aspheric lens of which curvature reduces asproceeding from the center toward the periphery. This substantiallyreduces the size of the lens 520 a as viewed in the direction x. This isdesirable for size reduction of the semiconductor light-emitting device101. As will be understood from FIG. 3, according to the aspheric lenshaving the above-described shape, of the light emitted from the LED chip300, the light rays having a relatively strong radiant intensity andemitted within a predetermined angle (e.g. about 10°) with respect tothe front direction of the LED chip 300 (in the direction of the opticalaxis La of the lens 520 a) travel substantially along the optical axisLa of the lens 520 a. Thus, according to the semiconductorlight-emitting device 101, light having a high intensity can be emittedin the direction of the optical axis La of the lens 520 a.

The detour portions 223, 224 and the mount portions 225, 226 are formedon the side surface 210 e, 210 f or the lower surface 210 b in a regionfrom a first end to a second end in the direction y. The surfaces of thedetour portions 223, 224 and mount portions 225, 226 are covered by theplating layer 220D. At the ends in the direction z, the bonding portion221, 222 are formed on the upper surface 210 a in a region from a firstend to a second end in the direction y. The ends of the bonding portions221, 222 in the direction z are exposed from the foundation portion 510and covered by the plating layer 220D (see FIG. 4). The plating layer220D has good wettability to solder. Thus, as will be understood fromFIG. 15, when the light-emitting device is mounted by using the mountportions 225 and 226, solder fillets Hf indicated by phantom lines areformed in such a manner as to cover the detour portions 223 and 224. Aswill be understood from FIG. 16, when the light-emitting device ismounted by using mount portions 227 and 228, solder fillets Hf indicatedby phantom lines are formed in such a manner as to cover the mountportions 225, 226, the detour portions 223, 224 and the bonding portions221, 222. Thus, the semiconductor light-emitting device 101 has enhancedbonding strength whether it is used as a top view type light source or aside view type light source. This is suitable for keeping the mountedstate on the circuit board S in a desired posture. In particular, in thecase shown in FIG. 16, the solder fillet Hf can be applied also onto thebonding portions 221,222 on the upper surface 210 a of the base 210.This realizes more reliable electrical connection between thesemiconductor light-emitting device 101 and the circuit board S.

Although Cu contained in the wiring pattern 220 (conductive layer 220A)is suitably used as a material for the wiring pattern 220, it isoxidized relatively easily. When Cu is oxidized, wettability of solderdeteriorates, so that bonding strength between Cu and solder reduceswhen solder is used for mounting. In this embodiment, however, the endsurfaces of the conductive layer 220A are covered by the plating layer220D. This makes it possible to avoid reduction of the bonding strengthin the case where solder is used for mounting.

In the case where the mount portions 227, 228 are used for mounting, thesemiconductor light-emitting device 101 is in a laid-down posture (seeFIG. 16). This posture may be relatively unstable, with the lens 520 aoverhanging largely from the mount portions 227, 228. However, the sidesurface 510 a of the foundation portion 510 of the resin package 500 isflush with the side surface 210 c of the base 210. This allows thesemiconductor light-emitting device 101 to be supported on the circuitboard S at a large area by the combination of the side surface 210 c ofthe base 210 and the side surface 510 a of the foundation portion 510,which stabilizes the posture in the mounted state. This is advantageousfor mounting the semiconductor light-emitting device 101 on a circuitboard S in a desired posture.

As described with reference to FIG. 3, the center of gravity G (thecenter of gravity of the entirety including the substrate 200, the LEDchip 300 and the resin package 500) is closer to the substrate 200 thanthe middle point C (the middle point between the lower surface 210 b ofthe base 210 and the top of the lens 520 a) is. With this arrangement,when the semiconductor light-emitting device 101 is mounted in alaid-down posture as shown in FIG. 16, the side surface 210 c of thebase 210 and the side surface 510 a of the foundation portion 510 aremade more parallel to the obverse surface of the board S. The height ofthe side surface 510 a of the foundation portion 510 (the thickness t ofthe foundation portion 510 in the direction x) can be increased in sucha manner that the center of gravity G is closer to the lens 520 a thanthe middle point C is. However, in view of the mounting as a top viewtype shown in FIG. 15, it is preferable for realizing stable mountingthat the gravity G is closer to the substrate 200 than the middle pointC is.

As described with reference to FIG. 3, the length L2 from the lowersurface 210 b of the base 210 to the end of the foundation portion 510on the first side in the direction x is not less than one half thelength L1 from the lower surface 210 b to the center of the lens 520 a.According to this arrangement, when the semiconductor light-emittingdevice 101 is mounted in a laid-down posture as shown in FIG. 16, only asmall proportion of the lens 520 a overhangs from the mount portions227, 228. This is suitable for stabilizing the posture of thesemiconductor light-emitting device 101 in the mounted state.

The side surface 210 d of the base 210, which is on the opposite side ofthe side surface 210 c in the direction y, and the side surface 510 b ofthe foundation portion 510 are flush with each other. Thus, when themounting is performed by utilizing the mount portions 227, 228 and byusing e.g. a chip mounter, the surface of a relatively wide area made upof the side surface 210 d of the base 210 and the side surface 510 b ofthe foundation portion 510 can be utilized as a surface to be sucked.This allows the operation for mounting the semiconductor light-emittingdevice 101 to be stably performed. Thus, this arrangement is suitablefor mounting the semiconductor light-emitting device 101 on the circuitboard S in a desired posture.

FIGS. 17 and 18 show a semiconductor light-emitting device according toa second embodiment of the present invention. In FIG. 17 and thesubsequent drawings, the elements that are identical or similar to thoseof the first embodiment are designated by the same reference signs asthose used for the foregoing embodiment, and the description is omittedappropriately.

As shown in FIG. 17, in the semiconductor light-emitting device 102 ofthis embodiment, the center of the lens 520 a is offset from the middlepoint between the side surface 210 c and the side surface 210 d of thebase 210 toward one side in the direction y (toward the side surface 210c), as viewed in the direction x. Moreover, in this embodiment, as shownin FIGS. 17 and 18, the dome-shaped portion 520 and the lens 520 a aremade small, as compared with those of the first embodiment. Note thateven in the case where the dome-shaped portion 520 and the lens 520 ahave the same size or be larger than those the first embodiment, itsuffices that the center of the lens 520 a is offset toward one side inthe direction y.

The semiconductor light-emitting device 102 of this embodiment can bemanufactured by a process similar to the above-described process formanufacturing the semiconductor light-emitting device 101. FIG. 19 showsa semiconductor light-emitting device aggregate member 102′ including abase aggregate board 210′, conductor patterns 220′, LED chips 300, wires400, and a resin mold 500′. (Hereinafter, this aggregate member, whichcorresponds to the aggregate member 101′ shown in FIG. 14, is referredto as aggregate member 102′). The aggregate member 102′ is cut along x-yplane at predetermined intervals in the direction y. In this embodiment,the aggregate member is cut at positions indicated by cutting lines CLin FIG. 19.

As shown in FIG. 20, when the semiconductor light-emitting device 102 isused as a side view type light source, it is mounted with the sidesurface 210 c, toward which the lens 520 a is offset, facing the circuitboard S. Thus, the center of gravity in the mounted state is positionedat a lower position (closer to the circuit board S) as compared withthat in the first embodiment (see FIG. 16). Thus, according to thesemiconductor light-emitting device 102, the posture is more stabilizedwhen mounted as a side view type.

FIG. 21 shows a semiconductor light-emitting device according to a thirdembodiment of the present invention. The semiconductor light-emittingdevice 103 of this embodiment differs from the foregoing embodiments inshape of the bonding portions 221, 222. In this embodiment, the bondingportion 221 has an extension 221A (first extension) extending from thefirst side (right side in this figure) toward the second side (left sidein this figure) in the direction z, and the LED chip 300 is mounted onthe extension 221A. For easier understanding, the region where thebonding portions 221, 222 are formed is indicated by upper left to lowerright hatching in FIG. 21. Also in FIGS. 22-24 which will be describedlater, the region where the bonding portions 221, 222 are formed isindicated by upper left to lower right hatching.

The extension 221A has a relatively large length L4 in the direction y.The length L4 of the extension 221A is not less than one half orpreferably not less than three fourths the length of the base 210 in thedirection y.

The extension 221A has openings 221 b penetrating in the thicknessdirection (direction x). In this embodiment, the extension 221A has aplurality of (two) openings 221 b spaced apart from each other. Theopenings 221 b are provided on the first side of the LED chip 300 in thedirection z. As will be understood from e.g. FIG. 3, at a region wherethe extension 221A is provided, the resin package 500 covering the uppersurface of the base 210 is in close contact with the surface of theextension 221A. On the other hand, at the regions where the openings 221b are provided, the resin package 500 is in close contact with thesurface of the base 210.

The extension 221A includes a projection 221 c and a pair of projections221 d. The projection 221 c projects from the center in the direction ytoward the second side in the direction z and overlaps the LED chip 300as viewed in the direction z. The length L5 of the projection 221 c fromthe LED chip 300 to the front end 221 e on the second side in thedirection z is relatively long. For instance, the length L5 is about0.2-0.6 mm or preferably about 0.3-0.6 mm. When described with referenceto the size of the LED chip 300, the length L5 is not less than thelength of the LED chip 300 in the direction y or preferably 1-2.5 timesor more preferably 1.5-2.5 times the length of the LED chip 300.

Each projection 221 d projects from each end in the direction y towardthe second side in the direction z. The front end 221 f of theprojection 221 d on the second side in the direction z is on the secondside (left side in the figure) of the front end 221 e of the projection221 c in the direction z.

The bonding portion 222 has an extension 222A (second extension)extending from the second side (left side in this figure) toward thefirst side (right side in this figure) in the direction z. The extension222A is positioned at the center in the direction y and has a relativelysmall length in the direction y. The wire 400, one end of which isbonded to the LED chip 300, is bonded at the other end onto theextension 222A.

In this embodiment, the diameter D1 of the lens 520 a (the diameter atthe portion where the upper surface of the foundation portion 510 meetsthe lens 520 a) is relatively large, and not less than six times orpreferably not less than eight times the length of a side of the LEDchip 300 (longer side when the LED chip 300 is in the form of anelongated rectangle) as viewed in the direction x.

The semiconductor light-emitting device 103 of this embodiment has thefollowing advantages, in addition to the advantages described above asto the first embodiment. In this embodiment, the LED chip 300 is mountedon the extension 221A. Heat generated from the LED chip 300 during thelighting of the LED chip 300 is transferred through the extension 221Amade of metal layers to the detour portion 223 and the mount portion225, and dissipated to e.g. the circuit board on which the mount portion225 is mounted. Since the length L4 of the extension 221A in thedirection y is relatively long, a large heat transfer path is securedfor the heat from the LED chip 300. According to this arrangement, heatfrom the LED chip 300 is efficiently dissipated to the outside, and goodhead dissipation ability is provided.

Epoxy resin or silicone resin forming the resin package 500 has higheradhesion to the glass epoxy resin forming the base 210 than to thesurface of the extension 221A (Au as the conductive layer 220C shown ine.g. FIG. 4). In this embodiment, the extension 221A has openings 221 bpenetrating in the thickness direction and arranged as dispersed, andthe resin package 500 is in close contact with the surface of base 210through the openings 221 b. According to this arrangement havingopenings 221 b, the resin package 500 and the base 210 are held in closecontact with each other at a sufficiently large area. This arrangementprevents detachment of the resin package 500 due to heat during thelighting of the LED chip 300.

In the extension 221A, the length L5 from the LED chip 300 to the frontend 221 e on the second side in the direction z is made relatively long.Further, the openings 221 b are provided on the first side of the LEDchip 300 in the direction z. Thus, the extension 221A is provided at arelatively large area around the LED chip 300. Thus, the heat generatedfrom the LED chip 300 is smoothly transferred toward the detour portion223 through the region of the extension 221A around the LED chip 300.This is desirable for enhancing heat dissipation.

FIG. 22 shows a semiconductor light-emitting device according to afourth embodiment of the present invention. The semiconductorlight-emitting device 104 of this embodiment differs from the foregoingembodiments in shape of the bonding portions 221, 222. Although thebonding portions 221, 222 of this embodiment have extensions 221A, 222Asimilarly to the third embodiment, the shapes of the extensions 221A,222A are different from those of the third embodiment.

In this embodiment, similarly to the third embodiment, the length L4 ofthe extension 221A in the direction y is made relatively long. Theextension 221A has a plurality of openings 221 b arranged on a circlearound the LED chip 300 at predetermined intervals. The extension 221Aalso has cuts 221 g at appropriate positions. Providing the openings 221b and the cuts 221 g as dispersed in this way is desirable for enhancingthe adhesion of the resin package 500.

The extension 221A has projections 221 d each projecting from each endin the direction y toward the second side in the direction z. Theprojection 221 d extends along a circle around the LED chip 300.

Since the semiconductor light-emitting device 104 of this embodiment hasthe extension 221A having a long length L4 in the direction y, thelight-emitting device has good heat dissipation ability similarly to thethird embodiment. Moreover, since the provision of the openings 221 band the cuts 221 g allows the resin package 500 and the base 210 to bein close contact with each other at a sufficiently large area, problemssuch as detachment of the resin package 500 are avoided.

FIG. 23 shows a semiconductor light-emitting device according to a fifthembodiment of the present invention. The semiconductor light-emittingdevice 105 of this embodiment differs from the foregoing embodiments inshape of the bonding portions 221, 222. Although the bonding portions221, 222 of this embodiment have extensions 221A, 222A similarly to thethird embodiment, the shapes of the extensions 221A, 222A are differentfrom those of the third embodiment.

In this embodiment, similarly to the third embodiment, the length L4 ofthe extension 221A in the direction y is made relatively long. Theopenings 221 b are formed at the same positions as those in the thirdembodiment, but the length L5 from the LED chip 300 to the front end 221e of the projection 221 c is made longer. Since the length L5 is long,the extension 222A is provided at a position deviated toward one side inthe direction y so as not to overlap the LED chip 300 as viewed in thedirection z.

Since the semiconductor light-emitting device 105 of this embodiment hasthe extension 221A having a long length L4 in the direction y, thelight-emitting device has good heat dissipation ability similarly to thethird embodiment. Moreover, since the provision of the openings 221 ballows the resin package 500 and the base 210 to be in close contactwith each other at a sufficiently large area, problems such asdetachment of the resin package 500 are avoided.

FIG. 24 shows a semiconductor light-emitting device according to a sixthembodiment of the present invention. In the semiconductor light-emittingdevice 106 of this embodiment, the shapes of the bonding portions 221,222 are the same as those of the semiconductor light-emitting device 105of the fifth embodiment. However, the semiconductor light-emittingdevice of this embodiment differs from the semiconductor light-emittingdevice 105 in that it includes resist films 231, 232.

As shown in FIG. 25, the resist films 231, 232 are interposed betweenthe bonding portions 221,222 and the resin package 500. The resist film231 covers the bonding portion 221, and the resist film 232 covers thebonding portion 222. The resist film 231 has an opening 231 a forexposing part of the bonding portion 231. The opening 231 a ispositioned at the center of the upper surface of the base 210. Foreasier understanding, the region where the resist films 231, 232 areformed is indicated by lower left to upper right hatching in FIG. 24.

As described above with reference to FIG. 4 and so on, when the bondingportions 221, 222 (wiring pattern 220) include conductive layers 220A,220B and 220C, the formation of conductive layers 220A, 220B, 220C andresist films 231, 232 is performed in the order of first the conductivelayer 220A, then the resist films 231 and 232, then the conductive layer220B and then the conductive layer 220C. The region where the conductivelayer 220A is formed corresponds to the region where the bondingportions 221, 222 are formed (see FIG. 24). As will be understood fromFIGS. 24 and 25, each resist film 231, 232 covers a conductive layer220A made of Cu in such a manner as to expose part of the conductivelayer 220A. Further, each resist film 231, 232 covers part of the base210. Here, an opening 231 a is formed in the resist film 231. Theconductive layer 220B made of Ni and the conductive layer 220C made ofAu are formed on the exposed portion of the conductive layer 220A. Inthis embodiment, the conductive layers 220B, 220C are formed in theopening 231 a and at the portion of the bonding portion 222 which is tobecome the extension 222A. In this way, extensions 221A, 222A areformed. The LED chip 330 is mounted on the extension 221A to face theopening 231 a.

Since the semiconductor light-emitting device 108 of this embodiment hasthe extension 221A having a long length L4 in the direction y, thelight-emitting device has good heat dissipation ability similarly to thethird embodiment. In this embodiment, resist films 231, 232 areinterposed between the bonding portions 221, 222 and the resin package500. The resist films 231, 232 have higher adhesion to the resin package500 than that of Au forming the conductive layer 220C. Thus, theprovision of the resist films 231, 232 is desirable for enhancing theadhesion of the resin package 500. Moreover, in this embodiment, thearea where the conductive layer 220C is formed is substantially small.This arrangement reduces the use of Au which forms the conductive layer220C.

FIG. 26 is a graph showing the results of simulation analysis performedwith respect to the heat dissipation ability of semiconductorlight-emitting devices. The graph of FIG. 26 shows temperature historiesafter the start of lighting with respect to the maximum reachingtemperature of the LED chip mount portion, in the case where a pluralityof kinds of semiconductor light-emitting devices which differ from eachother only in shape of the bonding portion on which the LED chip ismounted are lit. Examples 1 and 2 show the case of the semiconductorlight-emitting device 103 of the third embodiment and the case of thesemiconductor light-emitting device 104 of the fourth embodiment,respectively. In Comparative Example 1, the LED chip mount portion is inthe form of a small island, and a conductive portion having a smallwidth extends from the mount portion toward a detour portion. InComparative Example 2, which is a hypothetical model for comparison, thebonding portion is provided on the entire upper surface of the base.

As shown in the temperature histories in FIG. 26, Comparative Example 1reaches a considerably high temperature as compared with Examples 1, 2and Comparative Example 2. Thus, the durability of Comparative Example 1is considered to be low. Providing the bonding portion on the entireupper surface of the base 1 like Comparative Example 2 cannot berealized, because DC current cannot be applied to the LED chip. However,this structure provides an ideal level of heat dissipation abilitybecause the size of the bonding portion contributing to heat dissipationis the maximum. However, since adhesion of the bonding portion to theresin package is poor, problems such as detachment of the resin packageeasily occur in the structure of Comparative Example 2.

Examples 1 and 2 have only small temperature difference from ComparativeExample 2 and show good heat dissipation ability. Further, sinceExamples 1 and 2 (semiconductor light-emitting devices 103 and 104 ofthe third and the fourth embodiments) have better adhesion thanComparative Example 2 owing to the provision of the openings 221 b,enhanced durability is expected.

The semiconductor light-emitting device of the present invention is notlimited to the foregoing embodiments. The specific structure of eachpart of the semiconductor light-emitting device according to the presentinvention can be varied in design in many ways.

In the foregoing embodiments, the mount portions 227, 228 (second mountportion) are arranged in such a manner as to substantially avoid theside surface 210 c (first side surface) of the base 210 to expose thefirst side surface generally entirely. However, the present invention isnot limited to this arrangement. For instance, the second mount portionmay cover a relatively large region of the first side surface.

Although the materials for the conductive layers 220A, 220B, 220Cconstituting the wiring pattern 200 are exemplarily described in theforegoing embodiments, the present invention is not limited to this. Forinstance, as to the material for the conductive layer 220C that comesinto contact with the resin package 500, Ag may be used instead of Aufor enhancing adhesion to the resin package 500.

Although the foundation portion is provided in the foregoingembodiments, the foundation portion may not be provided. In this case,as to the portions other than the foundation portion, the structure ofthe foregoing embodiments can be applied. Also in the structure thatdoes not include the foundation portion, the diameter of the lens is notless than six times or preferably not less than eight times the lengthof a side of the LED chip as viewed in the direction x.

When the foundation portion is provided, the height of the foundationportion can be made smaller than that in the foregoing embodiment. Inthe foregoing embodiment, the length L2 from the lower surface 210 b ofthe base 210 to the end of the foundation portion 510 on the first sidein the direction x is not less than one half the length L1 from thelower surface 210 b to the center of the lens 520 a. However, the lengthL2 may be less than one half the length L1. Even in this case, theprovision of the foundation portion prevents the light-emitting devicefrom falling when mounted as a side view type.

The invention claimed is:
 1. A semiconductor light-emitting devicecomprising: a substrate including a base and a wiring pattern formed onthe base, the base including a first primary surface, a second primarysurface and a first side surface, the first primary surface and thesecond primary surface being spaced apart from each other in a firstdirection and parallel to each other, the first side surface beingconnected to both the first primary surface and the second primarysurface and facing in a second direction perpendicular to the firstdirection; an LED chip mounted on the first primary surface of the base;and a resin package covering the LED chip and including alight-transmitting lens and a light-transmitting foundation portion heldin direct contact with the light-transmitting lens, thelight-transmitting lens being positioned in front of the LED chip, thelight-transmitting foundation portion being closer to the substrate thanthe light-transmitting lens is in the first direction, thelight-transmitting foundation portion including a first foundationportion side surface that is flush with the first side surface of thebase, wherein the light-transmitting foundation portion includes a flatupper surface having a normal that is parallel to the first direction,the flat upper surface being in direct contact with thelight-transmitting lens, and a thickness of the light-transmittingfoundation portion in the first direction is larger than a thickness ofthe base in the first direction.
 2. The semiconductor light-emittingdevice according to claim 1, wherein the wiring pattern extends from thefirst primary surface and onto the second primary surface.
 3. Thesemiconductor light-emitting device according to claim 1, wherein thewiring pattern includes a first portion and a second portion formed onthe first primary surface and the second primary surface, respectively,and each of the first portion and the second portion of the wiringpattern extends at least to an edge of the first side surface of thebase.
 4. The semiconductor light-emitting device according to claim 1,wherein a center of gravity of an entirety including the substrate, theLED chip and the resin package is closer to the substrate than a middlepoint between the second primary surface and a top of the lens is. 5.The semiconductor light-emitting device according to claim 4, whereinthe base includes a second side surface spaced apart from the first sidesurface in the second direction, the second side surface being parallelto the first side surface, and wherein as viewed in the first direction,a center of the lens is offset in the second direction from a middlepoint between the first side surface and the second side surface.
 6. Thesemiconductor light-emitting device according to claim 1, wherein thebase includes a second side surface spaced apart from the first sidesurface in the second direction, the second side surface being parallelto the first side surface, and the light-transmitting foundation portionincludes a second foundation portion side surface parallel to the firstfoundation portion side surface.
 7. The semiconductor light-emittingdevice according to claim 6, wherein the second foundation portion sidesurface is flush with the second side surface of the base.
 8. Thesemiconductor light-emitting device according to claim 1, wherein thelight-transmitting lens includes an optical axis extending in the firstdirection and an aspheric surface having a curvature that decreases withincreasing distance from a center of the light-transmitting lens towarda periphery of the lens.
 9. The semiconductor light-emitting deviceaccording to claim 1, wherein the light-transmitting lens has a diameternot less than six times a length of a side of the LED chip as viewed inthe first direction.